- Video Introduction of the New Aztec AMC Evaporative Cooling Air Turnover System
- Designing Data Centers as Thermos Bottles
- A New Video on YouTube Describing How the Aztec Evap System Works
- Aztec To Be In Capacity North America Exhibit Hall
- Virtual Reality
- A Simple Concept That Saves Big Dollars
- Indirect Evaporative Cooling Research Project Launched
- Canadian Patent Granted for Mestex Digital High Turndown Burner
- So You Think Your Critical HVAC System Is Reliable?
- Aztec Provides Fresh Air Intake Penthouses for Data Centers in Northwestern US
- Shading and Make-Up for Building Designers
- Credibility and Trust
- How I Spent My Summer Vacation
- Too Hot to Handle? A Simple Reminder.
- Preaching to the Choir
- Evaporative Cooling Anaysis for Data Modules in Two Diverse Climates
- Aztec Indirect Evaporative Cooling System on Display at DFW ASHRAE Golf Outing
- How We Used To Do It
- Mestex, Division of Mestek YouTube Channel
- Aztec Evaporative Cooling for Data Centers at Data Center World
- GreenBuild Toronto
- Trane Division of Ingersoll-Rand in Lawsuit Over Wireless Technologies
- New BIM Objects From The Aztec Brand
- DOE Proposes Building Rating System
- The Importance of Correct Static Pressure for Direct Fired Make-Up Air Equipment
- Instant Online Document Lookup Using Microsoft Tags
- Do Evaporative Cooling Systems Use Too Much Water?
- Sustainability at Mestek Dallas
- Facebook Offers Their Outside Air Cooling Solution To All Data Center Owners
- Restaurant Energy Saving Idea That Can Be Used Anywhere
- Planning for Volatility
- Ever Wonder Where the Power Goes in a Data Center?
- ASHRAE TC 9.9 Expands Data Center Temperature Ranges Again
- Green Buildings Get Another Boost
- ASHRAE Show Report
- The Story of SHR or Why My Classroom is Stuffy
- CFD, Air Turnover, and the Pharmaceutical Industry
- It is not sustainable if it is not maintainable... or if it breaks down
- Accounting Rule Change Might Impact HVAC
- Reduce electrical demand load with an Aztec indirect evaporative cooling unit
- Lower Cost of Ownership with the Applied Air FAP
- Everything You Want to Know in a Flash
- Data Centers and Evaporative Cooling Webinar August 23
- New "Green" Product Announcement
- DDC Application Case Studies
- PowerPoint showing the importance of gas pressure, static pressure, and voltage
- Webinar: 'The Importance of Correct Gas Pressure, E.S.P. and Voltage'
- An Old Solution to a New Problem
Air Pollution and HVAC
Over the Christmas/New Years holiday break I was able to spend some time on the road crossing Texas, New Mexico, and parts of Arizona. While I saw plenty of interesting sights it is not the goal of this blog to create a travel channel. The goal is to highlight technologies and subjects of interest in the HVAC arena.
The subject that came to mind as I drove across these states was that of indoor air quality. Two areas, in particular, raised my attention to this topic. Phoenix, Arizona and El Paso, Texas were both covered with a thick layer of smog as I passed through those towns. The climatic reasons are not all that relevant to this discussion but the "temperature inversions" that are common in those areas at certain times of the year mean that smog will develop and stay trapped for hours, if not days. But those two cities are not alone. Los Angeles, California has been well known for poor air quality for years. New York City leaders have become concerned enough about outside air quality to include provisions in their new "Green Codes" that are intended to address the issue. Finally, attention has been brought by the folks at NOAA to the fact that pollution in China eventually makes it way to the US on the jet stream.
HVAC products can either help mitigate this problem or simply move it from the outdoors to the indoors. All buildings with occupants are required by building codes to have some amount of "ventilation air". It has been common practice to introduce that ventilation air through conventional air handlers or packaged rooftop equipment. In the vast majority of cases that equipment was designed, and is applied, with only the minimum level of air filtration included. The primary goal of the filtration has been to protect the components of the equipment from dust fouling and to provide a nominal level of indoor air quality improvement. New requirements and guidelines that specify MERV 11 and higher filtration are intended to let the equipment begin to mitigate the outdoor air quality before it enters the space. But how effective is this?
In a conventional HVAC system design there will be dozens of these filters, if not hundreds, scattered all over the building in numerous air handlers or packaged units. Maintaining all of these filters properly becomes an ongoing task. In addition, if even better filtration is required, or desired, the average piece of HVAC equipment simply lacks the space to provide more filtration.
Dedicated Outdoor Air Systems, or "DOAS", equipment helps address this. By isolating all of the ventilation air requirements into a single point, maintenance of the filtration system becomes much easier. In addition, some "DOAS" equipment, such as the Applied Air FAP, is designed to allow multiple stages of filtration. When combined with low airflow systems such as chilled beams the result can be very clean ventilation air even in areas such as those I drove through over the holidays.
As a final consideration for indoor air quality I would suggest that the old, ancient actually, technology of adiabatic or evaporative cooling might be considered. Although adiabatic or evaporative cooling can provide effective temperature control in vast parts of the United States it can also provide an extremely effective filtering system as well. Air is literally "washed" as it passes through the unit. As part of an overall system where the adiabatic or evaporative cooling system, such as the Alton or Aztec products, only provides the ventilation air and other equipment handles sensible and latent cooling the improvement in indoor air quality could be dramatic.